In ACNS 5.X Content Delivery Network what is the purpose of defining a root Content Engine for a channel?

A.
This Content Engine retrieves content from other Content Engines within the CDN.

B.
This Content Engine is used by the administrator to manage the Content Delivery Network.

C.
This Content Engine downloads the content from the origin server and distributes the content to all the Content Engines that belong
to the Channel.

D.
This Content Engine downloads the content from the Content Distribution Manager and distributes the content to all the Content
Engines that belong to the Channel.

E.
None of the above